taken 4 years ago, near to Boxley, Kent, Great Britain

Active Traffic Management, Northbound M20 near Boxley

Active Traffic Management (ATM) is a system used on certain motorways where gantry signs are computer-controlled to set a variable speed limit, open the hard shoulder as a running lane and limit the volume of traffic entering at junctions, with the aim of improving the flow of traffic (see Link (Archive Link ) for more detailed information about the Active Traffic Management system).

Here, the signs are showing that a (mandatory) speed limit of 60mph is in force.

The M20 is a 51 mile motorway running between the M25 motorway near Swanley and Folkestone in Kent. It was constructed from 1960. It is a key route for lorries connecting to mainland Europe via the Channel Tunnel and Ferries.